Fix prefer-includes fixer omitting parentheses (#287)

Author: chiawendt

rules/prefer-includes.js

@@ -12,13 +12,12 @@ const isIndexOf = node => {
 
 const isNegativeOne = (operator, value) => operator === '-' && value === 1;
 
-const getSourceCode = (context, node) => (
-	context.getSourceCode().getText(node)
-);
-
 const report = (context, node, target, pattern) => {
-	const targetSource = getSourceCode(context, target);
-	const patternSource = getSourceCode(context, pattern);
+	const sourceCode = context.getSourceCode();
+	const memberExpressionNode = target.parent;
+	const dotToken = sourceCode.getTokenBefore(memberExpressionNode.property);
+	const targetSource = sourceCode.getText().slice(memberExpressionNode.range[0], dotToken.range[0]);
+	const patternSource = sourceCode.getText(pattern);
 	context.report({
 		node,
 		message: 'Use `.includes()`, rather than `.indexOf()`, when checking for existence.',

test/prefer-includes.js

@@ -60,6 +60,11 @@ ruleTester.run('prefer-includes', rule, {
 			code: '\'\'.indexOf(\'foo\') < 0',
 			output: '!\'\'.includes(\'foo\')',
 			errors
+		},
+		{
+			code: '(a || b).indexOf(\'foo\') === -1',
+			output: '!(a || b).includes(\'foo\')',
+			errors
 		}
 	]
 });